The Central Laboratory Core is specially designed to provide virologic and immunologic support to Projects in this application. The mission of the NARL will be to help investigators set up their laboratories and provide training to their technicians in order to bridge the gap between different groups of investigators, maximize available technology and develop new techniques where necessary. In particular, the Core will be affiliating with the Data Management Center (SDMC) and Training Core at NCAIDS. The specific aims of the CIPRA CL are the following: 1. Provide laboratory based scientific leadership and consultation to CIPRA, collaborating organizations, and protocol teams. 2. Support and facilitate virologic studies of the CIPRA project 3. The immunology group of the CIPRA central laboratory at the national center for AIDS prevention and control will focus effort and resources on this unique opportunity, by supporting and facilitating studies in the area of vaccine studies and therapeutic trials (project) characterizing of responses in acute HIV infection in exposed-uninfected individuals and/or discordant couples (project) and Characterization of HIV cross-clade and clade-specific immunity (Project).